New Delhi: The indigenous under development Kaveri engine cannot be used in the TEJAS, but will be a building block for future engine development programs in India, Defence Ministry said on Monday.

In a reply to a question in Lok Sabha, Minister of State for Defence Ajay Bhatt said the project has achieved "higher Technology Readiness Level (TRL) in many critical technology domains and those technologies are being used in the various engine development programs of the country".

After 22 years, and over Rs. 2,000 crore being spent, Bhatt said the engines are used as test vehicles for validating next generation technologies.

"At present, the TEJAS is integrated with an imported engine. However, in future, it is proposed to develop indigenous engines for powering our own aircrafts such as TEJAS variants and AMCA in association with an International Engine House. The technological capabilities built through the Kaveri engine project will be utilised," Bhatt said.

"TEJAS, Flight Operational Clearance (FOC) configuration demands higher thrust than the intended engine requirement. Hence the Kaveri in the present architecture cannot be integrated. In order to induct with TEJAS, a modified engine version is require," he said.

The Cabinet Committee on Security (CCS) sanctioned Kaveri Engine project in 1989. The sanctioned fund was Rs. 2105 crore, and so far the expenditure is Rs. 2,035 crore, the minister said.

Gas Turbine Research Establishment under Defence Research and Development Organization is working on Kaveri Engine Program.

So far, nine full prototype engines and four core engines have been built, and over 3217 hours of engine testing has been conducted. The engine has completed Altitude tests and Flying Test Bed (FTB) trials.

"This is the first time that an indigenously developed military gas turbine engine was flight tested," the minister added.